1. Field of the Invention
This invention relates to a method and apparatus for filling a dispensing system with fluid in its liquid phase, the system enabling the liquid to subsequently vaporize into its gaseous phase for dispensing to users.
2. Description of the Prior Art
It is known to fill a dispensing system with a fluid in its liquid phase, with the system being operative to enable conversion of the fluid to its vapor or gaseous phase for dispensing, such as dispensing gaseous carbon dioxide to a carbonated drink dispenser.
U.S. Pat. No. 4,936,343, dated Jun. 26, 1990 and issued to John E. Pruitt et al, discloses a xe2x80x9cCarbon Dioxide Fill Manifoldxe2x80x9d comprising a manifold having a fill line which accepts fluid in its liquid phase from a storage vehicle or the like for completely filling one or more liquid storage containers to which it is connected, the liquid storage containers in turn being connected in series with one or more gas storage containers.
An atomizer disposed between the liquid and gas storage containers is operative to establish a proper ratio of liquid to gas in the dispensing system.
Each time a user dispenses some of the gas, the gas flows through the atomizer and develops a pressure differential between the liquid and gas storage containers. This differential increases as successive gas withdrawals occur. When a certain level of pressure differential is reached, an in-line pressure relief valve in the system opens to automatically permit additional, make-up liquid to flow through the atomizer and replenish the supply of available gas.
The added liquid vaporizes and expands into gas which fills the gas storage container or containers, according to the existing pressure differential to their original levels. Liquid/vapor flow continues through the atomizer until the requisite pressure differential is no longer present at the in-line relief valve. At that time the valve closes and shuts off further liquid flow. If overfilling occurs, such that some of the liquid flows into the portion of the gas storage container that is reserved for gas expansion, excess pressure can develop. Consequently, each gas storage container is provided with a rupture disc designed to fail when the container pressure exceeds a predetermined level. If overfilling is prohibitively high, the rupture disc fails and the contents of the container are jettisoned.
A similar system that employs a vaporizer or atomizer is disclosed in U.S. Pat. No. 5,113,905, dated May 19, 1992 and issued to Pruitt et al for a xe2x80x9cCarbon Dioxide Fill Manifold and Methodxe2x80x9d. The patent is based upon an application which is a continuation-in-part of the application which resulted in issuance of the above-discussed U.S. Pat. No. 4,936,343.
The atomizer of the ""905 patent includes an atomizer having a pressure actuated check valve located internally of the atomizer for periodically replenishing the supply of gas in response to the development of a selected pressure differential across the pressure actuated valve.
Various other analogous systems are provided in the prior art for dispensing a gaseous phase of a fluid such as carbon dioxide but many, like the two patents just described, are characterized by special relief valves, pressure actuated valves, vaporizers or the like. That is, a regulator such as a check valve or other pressure responsive device is used between the liquid and gaseous portions of such systems to control the change of liquid to gas. This results in a system that is relatively complex, expensive to maintain, and not as responsive to the needs of users as the method and apparatus of the present invention. As will be seen, in the system of the present invention there is no such regulator. All manifold passages are open and interconnected with no pressure differential between them.
According to the present invention, a system is provided which is particularly adapted for use as a carbonated beverage dispensing system. The system includes a manifold which can be connected to a supply truck or other source of carbon dioxide fluid in its liquid phase.
The manifold includes a controller in the form of a spool valve which is movable to a closed position by the pumping pressure developed when the liquid is pumped into the manifold from the liquid source. The incoming liquid flows around and through the closed spool valve into liquid passages in the manifold that are connected to a set of liquid storage cylinders. However, the flow of liquid is blocked by the spool valve from flowing into a dispenser passage which leads to the dispensing port through which the gaseous form of the fluid is dispensed to a user. The terms xe2x80x9cgasxe2x80x9d, xe2x80x9cgaseousxe2x80x9d and xe2x80x9cvaporxe2x80x9d are sometimes interchangeably used as a matter of convenience.
When the liquid storage cylinders are completely filled in the closed position of the spool valve by the incoming liquid flowing past the spool valve, the pump is turned off. The hose from the filling pump is vented when the pump is turned off, so the manifold pressure exceeds the pressure on the inlet or filling port, and the spool is shifted to its open position. The pump can be turned off manually, or automatically in response to an increase in pressure when the system is full of liquid. The liquid within the liquid storage cylinders is now undergoing vaporization, the rapidity of vaporization depending upon the magnitude of the vapor pressure in the system.
With the spool valve in its open position, fluid communication is provided between all of the manifold passages, i.e. the liquid passages, the gas passages, and the dispensing passage. The evolving gas then can flow through all of these passages and particularly into the gas storage container or containers.
There is no pressure differential between any of these passages. The production of gas can therefore occur without the use of any special vaporizer, atomizer or valving arrangement designed to respond to predetermined pressure differentials or the like to produce gas. The generation of gas automatically continues until the liquid has been substantially all vaporized and the resulting gas completely used. When this fill cycle is completed, and the liquid has been substantially all used, with the pump having been turned off and the spool valve moved to its open position by internal manifold pressure or, as will be seen, by bias means acting against the spool valve, the pump can again be manually turned on and the apparatus operated to initiate another fill/use cycle to introduce a fresh supply of liquid for the manifold from the supply vehicle.
Reference has been made to a spool valve type of controller but, as will be described, there are other types of valving arrangements which can be used, if desired, to provide the described functions of the spool valve.